Pattern Gaseous Detectors Research Articles

Spatial resolution studies using point spread function extraction in optically read out Micromegas and GEM detectors

Optically read out gaseous detectors are used in track reconstruction and imaging applications requiring high granularity images. Among resolution-determining factors, the amplification stage plays a crucial role and optimizations of detector geometry are pursued to maximize spatial resolution. To compare Micro Pattern Gaseous Detector (MPGD) technologies, focused low-energy X-ray beams at the SOLEIL synchrotron facility were used to record and extract point spread function widths with MICRO-Mesh Gaseous Structure (icromegas) and Gas Electron Multiplier (GEM) detectors. Point spread function width of ≈108µm for Micromegas and ≈127µm for GEM foils were extracted. The scanning of the beam with different intensities, energies and across the detector active region can be used to quantify resolution-limiting factors and improve imaging detectors using MPGD amplification stages.

The [formula omitted]-RWELL technology for tracking apparatus in High Energy Physics

The micro-Resitive WELL (μ-RWELL) is a Micro Pattern Gas Detector (MPGD) that inherits some of the best characteristics of existing MPGDs, like GEMs and MicroMegas, while simplifying the detector construction. A significant progress towards large-scale applications has been achieved through the consolidation and industrial cost-effective manufacturing of this technology. The μ-RWELL, showing excellent spatial performance, good time resolution and stability under irradiation, is proposed for several tracking apparatus for future experiments at future accelerators such as FCC (CERN), CEPC (China) and EIC (Brookhaven National Laboratory). The reduced impact in terms of material budget makes this technology suitable for the development of tracking devices in the muon spectrometer. In addition, the flexibility of the μ-RWELL base material makes this device suitable for the development of very light, fully cylindrical inner trackers at future high luminosity tau-charm factories, SCTF (China). We report in this paper some results in the development of 2D readouts for IDEA apparatus and the construction steps of a cylindrical μ-RWELL.

Corryvreckan framework integration for [formula omitted]-RWELL tracking detectors

This study is dedicated to enhancing the Corryvreckan framework, a versatile platform designed for the reconstruction and analysis of test beam data, by integrating an interface for the Scalable Readout System (SRS)+APV25 Front End Electronics (FEE). The SRS+APV25 represents the initial stage of a very popular readout chain for acquiring and processing Micro Pattern Gaseous Detectors (MPGD) signals. Initially, Corryvreckan was optimized by its developers for use with pixelated silicon-based detectors. This project, for the first time, aims to exploit all the potentialities of the Corryvreckan framework for the analysis of gaseous detectors data, specifically the μ-RWELL tracking detectors with strip readout. Detectors with different readout layouts were tested, thanks to the test beam carried out in June 2023 by the collaboration of FCC-ee, LHCb and CLAS12 groups. The analysis performed with Corryvreckan was benchmarked against the analysis conducted using the GRAAL framework, which is the standard tool currently employed, proving that Corryvreckan’s modular approach not only simplifies the process of adapting it to various types of detectors but also enhances the efficiency of data analysis by providing a streamlined, user-friendly interface.

Performance of a triple-GEM detector with capacitive-sharing 3-coordinate (X–Y–U)-strip anode readout

The concept of capacitive-sharing readout, described in detail in a previous study, offers the possibility for the development of high-performance three-coordinates (X–Y–U)-strip readout for Micro Pattern Gaseous Detectors (MPGDs) using simple standard PCB fabrication techniques. Capacitive-sharing (X–Y–U)-strip readout allows simultaneous measurement of the Cartesian coordinates x and y of the position of the particles together with a third coordinate u along the diagonal axis in a single readout PCB. This provides a powerful tool to address multiple-hit ambiguity and enable pattern recognition capabilities in moderate particle flux environment of collider or fixed target experiments in high energy physics HEP) and nuclear physics (NP). We present in this paper the performance of a 10 cm × 10 cm triple-GEM detector with capacitive-sharing (X–Y–U)-strip anode readout. Spatial resolutions of the order of σxres = 71.6±0.8μm for X-strips, σyres = 56.2±0.9μm for Y-strips and σures =75.2±0.9μm for U-strips have been obtained at a beam test at Thomas Jefferson National Accelerator Facility (Jefferson Lab). Modifications of the readout design of future prototypes to improve the spatial resolution and challenges in scaling to large-area MPGDs are discussed.

Studies on a hadronic calorimeter with MPGD technology for a future Muon Collider experiment

In the context of the European strategy for particle physics, the Multi-TeV Muon Collider has emerged as a compelling alternative for advancing our understanding of the Standard Model, after the full exploitation of the High-Luminosity LHC. The physics programme at the Muon Collider includes precise measurements in the Higgs boson sector and the search for new physics at the TeV scale. Achieving these goals relies on accurate full event reconstruction, including the identification and precise four-momentum estimation of various particles. The Particle Flow (PF) algorithm is one of the most suitable approach for this task, exploiting information from tracking, calorimeter, and muon detectors for particle identification and measurements of their momenta/energies. Tracking detectors measure charged particle momenta, while calorimeters provide energy measurements for photons and neutral hadrons. Therefore, a combination of an exceptional tracking system and high-granularity calorimeters is necessary. However, one of the biggest challenges for a future experiment at the Muon Collider is to discriminate the product of the μμ collisions from the intense beam-induced-background (BIB), due to the unstable nature of muons, whose decay products interact with the detector material. To address this, an innovative hadronic calorimeter (HCAL) based on Micro Pattern Gas Detectors (MPGDs) is proposed. MPGDs offer robust technology for high radiation environments and a high granularity for precise spatial measurements. Dedicated studies are needed to assess and optimize the performance of an MPGD-based HCAL, including the development of medium-scale prototypes for performance measurements. The response of HCAL to incoming particles is examined through Monte Carlo simulations using Geant4, comparing the performance of digital and semi-digital readouts, with energy resolution as the figure of merit. The simulated geometry will be integrated into the Muon Collider software to study its impact on jet reconstruction within the full apparatus and in the presence of BIB. The simulation will be also validated through the test of a small-size calorimeter cell equipped with advanced resistive MPGD technologies, namely resistive MicroMegas, resistive μRWELL and RP-WELL.

First results on MPGD prototypes in test beam for MPGD-based HCAL at a future Muon Collider experiment

The Multi-TeV Muon Collider will allow significant advancement in particle physics and in the understanding of its Standard Model for the era after the High-Luminosity LHC. The Muon Collider physics program involves precise Higgs boson sector measurements and TeV-scale new physics exploration. These goals demand accurate full-event reconstruction. The Particle Flow algorithm, which utilizes tracking, calorimeter, and muon detectors, is ideal for identifying and precisely estimating particle momenta/energies and can accomplish this task. Tracking detectors measure charged particle momenta, while calorimeters provide energy measurements for photons and neutral hadrons. Therefore, combining an exceptional tracking system with high-granularity calorimeters is essential. A major challenge is discerning μμ collision products from beam-induced-background, due to muon decay. To address this, an innovative hadronic calorimeter (HCAL) using Micro Pattern Gas Detectors (MPGDs) is proposed. MPGDs provide robust technology for high radiation and ensure precise spatial measurements. Dedicated studies are needed to assess and optimize the performance of an MPGD-based HCAL, including the development of medium-scale prototypes for performance measurements.This article describes the studies for a hadronic calorimeter based on MPGDs, relying on advanced technologies such as μ-rwell, resistive MicroMegas, and RPWELL. To assess the performance of MPGD detectors, a test beam was conducted in July 2023 at the Super Proton Synchrotron at CERN. This test beam aimed to evaluate the performance of MPGD detectors with 1×1 cm2 pad readout under beam irradiation. Preliminary results from this test are presented.

New generation B-Field and RAD-tolerant DC/DC power converter for on-detector operation

The increase in the number of readout channels in new detectors, like the Micro Pattern Gas Detectors (MPGD), in the order of several millions, requires a large amount of electrical power to supply the front-end electronics, up to hundreds kW. If this power is generated at long distances from the detector, the voltage drop on the connection cables puts serious constraints to the supply current, to the wire cross-section and to the power distribution. A large amount of voltage drop on the cables, apart an increased power dissipation on wire resistance, determines regulation issues on the load in case of current transients. To mitigate these problems, a new generation DC/DC converter, working in a heavily hostile environment and with a power density greater than 200 W/dm3, was developed. It is modular, with up to four independent modules, eight channels each, collected in a water-cooled crate, and can supply the load with an adjustable 10 to 12 V output up to 170 W per channel. In this contribution, the design constraints of such a converter are analysed, taking as a basis the environmental, electrical and mechanical requirements of the ATLAS New Small Wheel (NSW) project. Thermal considerations require the converter to be water-cooled, and the dimensional constraints impose the adoption of an innovative design to convey the dissipated heat towards the heat exchanger. The control and monitoring system allows for the full remote management of the converter. Main electrical parameters were measured and are reported. The converter was also characterized in a harsh working environment, with radiation tests in the CERN CHARM facility beyond the limits estimated for ten years operation in ATLAS, and with magnetic field tests in various orientations, using different magnets at CERN up to 1.3 T. A better common mode noise filtering design improvement was implemented after the first characterization. Final performance measurements after the modifications are also reported.

A commentary on two NIM A papers by P. Gasik et al. and D. Attié et al. on R&D on, and applications of, micro pattern gas detectors

A commentary on two NIM A papers by P. Gasik et al. and D. Attié et al. on R&D on, and applications of, micro pattern gas detectors

PARSIFAL: A toolkit for triple-GEM parametrized simulation

PARSIFAL (PARametrized SImulation) is a fast and reliable software tool that reproduces the complete response of a triple-GEM detector to the passage of a charged particle, taking into account the main physical effects. Starting from the detector configuration and the particle information, PARSIFAL reproduces ionization, spatial and temporal diffusion, effect of magnetic field, if present, and GEM amplification to provide the dependable triple-GEM detector response. In the design and optimization stages of this kind of detectors, simulations play an important role. Accurate and robust software programs, such as GARFIELD++, can simulate the transport of electrons and ions in a gas medium and their interaction with the electric field, but they are CPU-time consuming. The necessity to reduce the processing time while maintaining the precision of a full simulation is the main driver of this work. For a given set of geometrical and electrical settings, GARFIELD++ is run once-and-for-all to provide the input parameters for PARSIFAL. Once PARSIFAL is initialized and run, it produces the detector output, including the signal induction and the output of the electronics. The results of the analysis of the simulated data obtained with PARSIFAL are compared with the results of the experimental data collected during a testbeam: some tuning factors are applied to the simulation to improve the agreement. This paper describes the structure of the code and the methodology used to match the output to the experimental data. Program summaryProgram Title: PARSIFALCPC Library link to program files:https://doi.org/10.17632/rg85kzjwwj.1Developer's repository link:https://github.com/Hilldar/PARSIFAL (branch triplegem)Licensing provisions: GPLv3Programming language: C++Nature of problem: Monte Carlo (MC) simulations are widely used in design and development of detectors for high energy physics as well as during data taking to understand how the detector geometry, acceptance, efficiency affect the experimental observations and hence infer the systematic effects. For triple-GEM detectors (one of the most used Micro Pattern Gaseous Detectors), the simulation of their response to the passage of particles is usually performed with GARFIELD++ (CERN) which provides a microscopic description of the signal creation, from the interaction of the particle with the gas to the induction of the signal on the anode. This detailed simulation is heavy and CPU-time consuming, hence it requires long computing periods to gain high statistics.Solution method: PARSIFAL software provides the MC simulation of the response of a triple-GEM detector to the passage of a charged particle by splitting the simulation into four independent steps: ionization, electron drift in gas and magnetic field, avalanche formation in the multiplication stages, signal induction on the anode and response of the electronics (APV-25 chip). For each step, PARSIFAL samples the variables of interest from distributions, obtained by using a set of input parameters. These parameters are extracted from a simulation run only once with GARFIELD++. Since the sampling is much faster than a full GARFIELD++ simulation, this reduces the CPU-time to collect a sample with high statistics. The results extracted by the PARSIFAL simulation have been tuned with experimental data collected during a testbeam at CERN and show a satisfactory compatibility.

The industrial production of Micro Pattern Gaseous Detector: experience from the ATLAS Micromegas

Resistive Micromegas is one of the detector technologies chosen by ATLAS for the Phase-1 upgrade of the Muon Spectrometer, completed in 2022 in view of the LHC Run3 start.It is the largest MPGD-based detector system ever built, covering an active area of 1280 m2, providing trigger and precise tracking capabilities to the ATLAS Muon system and able to stand a radiation background rate up to 20 kHz/cm2.The heart of the ATLAS Micromegas detectors is the anode board, which carries the resistive protection layer, the readout electrodes and the insulating spacers supporting the micro-mesh.The production of the 2048 readout boards of size up to 0.5×2.2 m2 has been assigned to high-technology PCB industries and required dedicated efforts for technology transfer, production follow-up and quality assurance and control.The paper reviews the main challenges from the design phase to the completion of the project which spanned over several years. Emphasis is also put on the thorough quality assurance and quality control protocol established, the achieved results, as well as on the logistic, supply and schedule constraints.The lessons learned from this unprecedented MPGD project are also discussed.

Studying signals in particle detectors with resistive elements such as the 2D resistive strip bulk MicroMegas

Abstract As demonstrated by the ATLAS New Small Wheel community with their MicroMegas (MM) design, resistive electrodes are now used in different detector types within the Micro Pattern Gaseous Detector family to improve their robustness. The extended form of the Ramo-Shockley theorem for conductive media has been applied to a 1 MΩ/□ 2D resistive strip bulk MM to calculate the signal spreading over neighbouring channels using an 80 GeV/c muon track. For this geometry, the dynamic weighting potential was obtained numerically using a finite element solver by applying a junction condition and coordinate scaling technique to accurately represent the boundary conditions of a 10 × 10 cm2 active area. Using test beam measurements, the results of this model will be used to benchmark this microscopic modelling methodology for signal induction in resistive particle detectors.

Ready for LHC Run III: the ATLAS New Small Wheel and the MicroMegas chambers performances

The two New Small Wheels (NSW) for the upgrade of the ATLAS Muon Spectrometer are now installed in the experiment and ready to collect data in LHC Run III, started in July 2022. The NSW is the largest Phase-1 upgrade project of ATLAS. Its challenging completion and readiness for data taking is a remarkable achievement of the Collaboration. The two wheels (10 meters in diameter) replace the first muon stations in the high-rapidity regions of ATLAS and are equipped with multiple layers of two new detector technologies: the small strips Thin Gap Chambers (sTGC) and the MicroMegas (MM). The latter, belong to the family of Micro Pattern Gaseous Detectors (MPGD), for the first time used in such a large scale in HEP experiments. Each detector technology will cover more than 1200 m2 of active area. The new system is designed to assure high tracking efficiency, reduction of fake trigger rates and precision measurement of muon tracks, also in view of the higher background environment foreseen for Hi-Lumi LHC. In this presentation, the motivation of the NSW upgrade and the steps from the commissioning to the data taking together with the first results using the Run III data will be presented, focusing on the MicroMegasperformances.

The high voltage system the novel MPGD-based photon detectors of COMPASS RICH-1 and its development towards a scalable HVPSS for MPGDs

The COMPASS RICH-1 detector underwent major upgrade in 2016 with the installation of four novel MPGD-based photon detectors. They consist of large-size hybrid MPGDs with multi-layer architecture composed of two layers of Thick-GEMs and bulk resistive Micromegas. A dedicated high voltage power supply system, realized with commercial devices, has been put in operation to protect the detectors against errors by the operator, monitor and log voltages and currents at a 1 Hz rate, and automatically react to detector misbehavior; it includes also the HV compensation for the detector gas pressure and temperature variations.The needs posed to the high voltage power supply systems by the operation of Micro Pattern Gaseous Detectors pushed the development of a novel single channel HV system able to overcome the performance of the commercial devices in terms of high-resolution diagnostic features and intelligent dynamic voltage control. In this talk the COMPASS HV system and its performance are illustrated, as well as the stability of the novel MPGD-based photon detectors during the physics data taking at COMPASS. The performance of the novel single channel power supply system when connected to a single photon Micro Pattern Gaseous Detector is presented in realistic working condition during a test beam with the preliminary results of multiple channels operation.

Design and studies of thick Gas Electron Multipliers fabricated in India

THick Gas Electron Multipliers (THGEMs) are robust and high gain Micro Pattern Gaseous Detectors which are economically manufactured by standard drilling and etching of thin printed circuit boards. In this paper, we present our recent simulation as well as experimental studies on THGEMs which have been fabricated in India using local expertise. Two types of THGEMs have been fabricated; one set has holes without any external rim and another set has holes with rims. These detectors have been characterized using argon-carbon dioxide and argon-isobutane gas mixtures. Electron transmission, effective gain, energy resolution, optimized working range and charging up studies have been presented for both the sets of THGEMs.

Observation on the bias current variation of a single mask triple GEM chamber

Gas Electron Multiplier (GEM) detector, one of the advanced members of the Micro Pattern Gas Detector (MPGD) group, is widely used in High Energy Physics (HEP) experiments. The high rate handling capability and spatial resolution make it a desired tracking detector for high rate HEP experiments. Investigation of the long-term stability is an essential criterion for any tracking device used in HEP experiments. To investigate the long-term stability of a Single Mask (SM) triple GEM detector prototype, it is irradiated continuously using a 55Fe X-ray source of energy 5.9 keV. The chamber is operated with Ar/CO2 gas mixture in continuous flow mode. The gain and energy resolution of the chamber are calculated from the 5.9 keV X-ray peak and studied as a function of time. The applied voltage, divider current and also the environmental parameters (ambient temperature, pressure and relative humidity) are recorded continuously. It is observed that at a fixed applied voltage, the divider current of the detector is changing with time and as a result, the gain of the detector also changes. A systematic investigation is carried out to understand the probable reasons behind the observed variation in divider current and also to find its possible remedies. The details of the experimental setup, methodology and results are discussed in this article.

Charging-up effect and uniformity study of a single mask triple GEM detector

The Gas Electron Multiplier (GEM) detector is one of the advanced members of the Micro Pattern Gas Detector (MPGD) family, used in High Energy Physics (HEP) experiments as a tracking device due to its high rate handling capability and good spatial resolution. The uniformity in the performance of the detector is an essential criterion for any tracking device.The presence of the dielectric medium (Kapton) inside the active volume of the GEM chamber changes its behaviour when exposed to external irradiation. This phenomenon is known as the charging-up effect. In this article, the charging-up effect over the entire surface of a Single Mask (SM) triple GEM chamber of dimension 10 cm × 10 cm is reported. The study of uniformity in terms of gain, energy resolution and count rate for the same chamber is also presented before and after the charging-up of the GEM foils.

Performance of a resistive micro-well detector with capacitive-sharing strip anode readout

The present study is carried out to demonstrate a new type of high-performance readout structure with low readout channel count developed for large-area micro pattern gaseous detectors. The structure exploits capacitive coupling between a vertical stack of 5 μ m thick copper pad layers sandwiched between 50 μ m thick polyimide foils to simultaneously transfer and spread the avalanche charges from the gaseous detector’s amplification structure to several strips or pads in the anode readout plane. The unique feature of the lateral spread of the avalanche charge size on several readout strips or pads is possible owing to well-defined configuration and sizes of the pads in layers of the vertical stack. This is known as a “capacitive-sharing” readout structure and this opens the door for high spatial resolution performance with low readout channel counts for large-area Micro Pattern Gaseous Detectors. Capacitive-sharing readout structures are fabricated using standard printed circuits boards manufacturing process. The concept is highly versatile as it can easily be implemented in any type of Micro Pattern Gaseous Detector’s amplification structure (Gas Electron Multipliers, micro-mesh gaseous structures, resistive micro-well detectors) and with a wide range of readout patterns (pads, strips, zigzags etc.). The technology also has a high degree of flexibility in terms of readout segmentation (pads or strip) pitch, with minimum impact on spatial resolution performances. The present study provides a detailed description of the capacitive-sharing readout concept and discusses a small resistive micro-well detectors prototype assembled with a two-dimensional capacitive-sharing strip readout structure as a proof of concept and with strip pitch of 800 μ m in both X and Y direction. The prototype was characterized in electron beam in the Hall D Beam Test setup at Jefferson Lab and a spatial resolution of (60 ± 1) μ m was achieved for both X and Y strips with an efficiency of (98.0 ± 0.9) % at the plateau and a signal arrival time jitter between neighboring strips less (6.00 ± 0.04) ns. Finally, we explore new ideas to expand the concept of capacitive-sharing readout structures to large particle detectors for future large scale particle physics experiments.

The micro-RWELL detector for the phase-2 upgrade of the LHCb muon system

The micro-RWELL detector (μ-RWELL) is a single amplification stage resistive Micro Pattern Gaseous Detector (MPGD), based on a copper-clad polyimide foil patterned with a micro-well matrix coupled with the readout PCB through a DLC resistive film (10÷100MΩ/□). For the phase-2 upgrade of the LHCb experiment, proposed for the LHC Run-5, the excellent performance of the current muon detector will need to be maintained at 40 times the pile-up level experienced during Run-2. Requirements are challenging for the innermost regions of the muon stations: the detectors should exhibit a rate capability up to 1MHz/cm2 and they are supposed to integrate a charge up to ∼1C/cm2. In this framework an intense optimization program of the micro-RWELL technology has been launched in the last year, together with a technology transfer to the industry operating in the PCB field. In order to fulfill the requirements, a new layout of the detector with a very dense current evacuation grid of the DLC has been designed. The detector, co-produced by the CERN-EP-DT-MPT Workshop, lead by one of the authors, and the ELTOS Company, has been characterized in terms of rate capability exploiting a high intensity X-ray Philips 2217/20 gun with a spot size (10÷50mm diameter) larger than the DLC grounding-pitch. A rate capability exceeding 10MHz/cm2 has been achieved, in agreement with previous results obtained with m.i.p. at the Paul Scherrer Institute (PSI) in Villigen (CH). A long term stability test is in progress: a charge of about 5mC/cm2 has been integrated over a period of about 16 days. The test will continue, in harder conditions (larger gain and X-ray flux), with the goal to integrate about 1C/cm2 in one year, while a slice test of the detector is under preparation.

High granularity small-pad resistive micromegas for rates above MHz/cm[formula omitted

An R&D project has been recently started to consolidate the technology of resistive Micromegas for operations well beyond the actual operations at HEP experiments, aiming at stable, reliable, and high gain operation up to particle fluxes of the order of 10 MHz/cm2, over large surfaces.To cope with these challenges, readout copper pads, of a few mm2 size, have been proposed to reduce the occupancy of the readout elements, calling for innovative solutions for the spark protection resistive scheme. It is known that single stage amplification Micro Pattern Gaseous Detectors suffer from sparks when operated under harsh environments. Resistive anodes drastically mitigate the spark intensities but, on the other hand, they reduce the rate capability when high currents flow into the detectors, generating a drop in the amplification voltage. Ad-hoc solutions must be adopted.Two resistive schemes have been studied. The first one is based on a pad-patterned resistive double layer, superimposed to the readout pads, with an embedded resistor connecting the resistive pads. In this scheme, each pad is independent from the others. The second scheme exploits the recently developed Diamond-Like Carbon (DLC) resistive foils. A double layer of DLC is superimposed to the readout pads, with a grid of interconnecting vias to ground for a fast evacuation of the accumulated charge. In this case the pads are not completely independent since the charge can spread over more pads. For each of these resistive schemes, detectors with different configurations and construction techniques have been built.All detectors have been thoroughly tested and fully characterized with radioactive sources, X-rays and with test beams carried out at CERN in 2021. The performance and achievements in terms of gains, rate capabilities, energy, space and time resolutions will be reported, along with a detailed comparison among the different schemes and configurations.

Effective Gain and Ion Back Flow study of triple and quadruple GEM detector

Gas electron Multipliers (GEM) are a new generation of gaseous avalanche devices in the Micro Pattern Gaseous Detector (MPGD) category. GEMs are widely used in both nuclear and high energy experiments as well as in medical science. Several parameters define the performance of these types of devices under various experimental conditions. This article focuses on the study of effective gain and Ion Back Flow (IBF) in both triple and quadruple GEM detectors. Effective gain and IBF are two of the most important parameters in determining the performance of GEM detectors.